The correct answer is D. Align focus . In Function Analysis, the team defines what the subject must do, not what its parts are. SAVE’s study guidance states that functions are described using two-word active verb/measurable noun pairings, and FAST is used to show how project functions relate to each other. ( )

For prescription eyeglasses, the basic function is correct vision . On the Function Logic Path, the “how” question asks: How do eyeglasses correct vision? The best functional answer is align focus because prescription lenses bend and direct light so the image focuses correctly for the user. This directly supports the basic function.

The other choices are supporting or secondary functions. Secure position helps hold the glasses properly on the face, but it does not itself correct vision. Minimize weight improves comfort, and improve durability supports dependability, but neither explains the direct functional mechanism of vision correction. FAST logic is specifically used to map these function relationships through How/Why reasoning, making align focus the correct lower-order function linked to “correct vision.” ( )

References/topics: Function Analysis Phase; FAST Diagramming; Function Logic Path; Basic Function; Lower-Order Function.